The long-term objective of this work is the development of an improved scientific basis for the analysis of child language transcript data and the application of this improved methodology to specific research problems. The specific aims are 1) to apply the new methodology to the developmental study of the lexicon, lexical semantics, syntactic patterns, phonological abilities, individual differences, cross-linguistic data, and data on input and interaction, 2) expand the scope and precision of the Child Language Data Exchange System (CHILDES) database, 3) promote researchers' access to the database, and 4) improve computational techniques for analysing the CHILDES database. The methodological approach being used in this work involves 1) the entry of transcript data into the computer, 2) organization of these data according to the standard CHILDES transcript format, 3) specification of research questions in terms of particular computational analyses, 4) using preexisting programs to conduct these analyses or writing new programs where necessary, and 5) analysing the outputs of the computer searches in terms of the standard statistical methods. These new techniques and new studies are of great importance to the study of normal and abnormal language acquisition, the child's role in the family and the community, and our understanding of cultural and familial differences in development and chile-rearing. The techniques of transcript analysis being developed are also readily applied to the study of adult doctor-patient and therapist-patient interactions.